MlCROSPORA 169 



Synopsis of Species 



Filaments large, cell-walls 1.5-3^ thick. 



Cells nearly cylindrical, diameter 28-33^, 1-1.6 times as long. I. M. crassior. 



Cells nearly cylindrical, diameter 21.5-25 a, 1-2 times as long. 2. M. amoena. 



Cells somewhat tumid, diameter 16.5-20^, 1-2 times as long. 3. M. Loefgrenii. 



Cells perfectly cylindrical, diameter 19.5-20 u, 1-2*4 times as long. 



4. M. Wittrockii. 

 Filaments smaller, cell-walls thin. 



Cells cylindrical, diameter 14-17 //. 5. M. floccosa. 



Cells cylindrical, diameter 1 1-14/z. 6. M. Willeana. 



Cells cylindrical, diameter 7.5—9.5 ^. 7. M. stagnorum. 



Cells slightly constricted, diameter 6.7-9.5^. 8. M. twnidula. 



Cells cylindrical, diameter 5.5-7 //. 9. M. quadrata. 



i. Microspora crassior (Hansg.) 

 M. amoena crassior Hansg. Sitz.-ber. K. Bohm. Gesell. Wiss. 

 1889 1 : 129. 1889; Prod. Alg. Bohm. 2 : 223. 1893. Schmidle, 

 Ber. Deutsch. Bot. Gesell. II : 544. 1893. 



M. amoena crassa Schmidle, Ber. Nat. Gesell. Freib. 7 : 75. 

 //. 2.f. 1. 1893. 



M. amoena forma crassior Wille, Rhodora, I : 149. 1899.* 



Filaments long and dark green : cells nearly cylindrical, 



28-33 f J - m diameter, 1-1.6 times as long ; cell-wall 2.5—3 A* thick, 



the lamellate structure often distinct ; chromatophore dense, usually 



covering the whole cell-wall and obscuring the large nucleus (pi. 



Exsic. : Phyc. Bor. Am. 616 p.p. Bridgeport, Conn., April, 

 1893 (I. Holden). (?) 



Growing in thick, tangled masses in rapid water, or as scattered 

 filaments with M. amoena or M. Loefgrenii. 



New York: Larchmont, May (588); Van Cortlandt Park, 

 June (632) ; Central Park, June (620), September (490), October 



(659)- _ 



This species is distinguished from M. amoena, chiefly by its 



* Schmidle (1900) quotes as an additional synonym Microspora DeToniana 

 Lagerh. Nuova Notarisia, 4 : 137. 1893, an d states that of the three names proposed by 

 himself, Hansgirg, and DeToni in the year 1893 it is difficult to decide which has 

 priority. He has overlooked the fact that Hansgirg' s variety was actually established 

 in 1889. Schmidle also thinks it probable that Conferva Raciborskii Gutwinski (Flora 

 Glon. Galicyi 7. pi. j. f. 1. 1892 ; Nuova Notarisia, 3 : 17. 1892) is to be identified with 

 this form. The correctness of such an identification appears to us to be more than 

 doubtful ; certainly the form called C. Raciborskii by West (Journ. Bot. 31 : 98. pi. 

 333' f- Q- 1893) differs widely from Microspora crassior, in its smaller diameter and 

 much thicker cell -wall. 



